Gibberling Disease

It starts with the eyes. A glaze, a drift, the way someone's attention slides off the conversation like water off hot steel. They were right there a moment ago, nodding along, part of the circle. Then something slips, and they are somewhere else entirely.
  Gibberling Disease is not a pathogen in the traditional sense. There is no wound to clean, no toxin to flush, no parasitic invader burrowing through tissue. It is a psionic and behavioral affliction, a disconnection between the mind and the shared reality it inhabits. The Infection within the brain begins to misfire as coherent thought collapses under the weight of nonsense and distraction. The tether between the individual and the world frays, and the Infection fills the silence with static.
  The causes are internal. Gibberling Disease arises spontaneously when an individual's mind drifts too far from structured, logical engagement with their surroundings. Prolonged mental disconnection from the ongoing logic of events, patterns of thought that make no sense within the current context: these are the triggers. It cannot spread through touch, air, or physical contact. What it can do, and what makes it unsettling in group settings, is spread confusion. One person's mental detachment generates frustration and disorientation in those around them, a social contagion that compounds the original break.
  Symptoms begin subtly. Distracted behavior, fragmented speech, sudden shifts in tone. The afflicted may appear confused by their surroundings, forget what was happening mid-sentence, or respond to questions that nobody asked. As the condition worsens, words break apart. Language dissolves into incoherent babble, punctuated by bursts of excitement or laughter that have no connection to anything happening nearby. Gestures become exaggerated; logic gives way to raw sound and motion. Communication collapses into grunts, nonsensical noises, and expressions that mean nothing to anyone but the afflicted.
  At its worst, the host becomes fully disconnected from shared perception. They no longer see or respond to the same reality as everyone else, often staring ahead as though watching something invisible. They become a living source of psychic dissonance, their presence pulling at the concentration of those nearby.
  What makes Gibberling Disease unusual among the ailments of the wasteland is its cure. No surgery, no herbs, no rare components. The only known treatment is reorientation: the afflicted must find their way back to the shared reality they left behind. Attention, patience, and a grounding reminder that the mind must stay tethered to the world it inhabits. Once that reconnection happens, symptoms fade and coherence returns. Death, as always, is the blunter solution; it cures Gibberling Disease at any stage.
  The disease carries no mechanical threat to the body. No organ fails, no tissue decays, no bones splinter. The damage is entirely to connection, to presence, to the fragile consensus that allows a group of survivors to function together. In a world where cooperation is the difference between standing and falling, that kind of damage is its own form of danger.